[comment {-*- tcl -*- doctools manpage}]
[manpage_begin tcl::transform::observe n 1]
[keywords {channel transformation}]
[keywords observer]
[keywords {reflected channel}]
[keywords {stream copy}]
[keywords {tip 230}]
[keywords transformation]
[keywords {virtual channel}]
[copyright {2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
[moddesc   {Reflected/virtual channel support}]
[category  Channels]
[titledesc {Observer transformation, stream copy}]
[require Tcl 8.6]
[require tcl::transform::core [opt 1]]
[require tcl::transform::observe [opt 1]]
[description]
[para]

The [package tcl::transform::observer] package provides a command
creating a channel transformation which passes the read and written
bytes through unchanged (like [package tcl::transform::identity]), but
additionally copies the data it has seen for each direction into
channels specified at construction time.

[para] Related transformations in this module are
[package tcl::transform::adler32],
[package tcl::transform::counter],
[package tcl::transform::crc32], and
[package tcl::transform::identity].

[para] The internal [package TclOO] class implementing the transform
handler is a sub-class of the [package tcl::transform::core]
framework.

[section API]

[list_begin definitions]

[call [cmd ::tcl::transform::observe] [arg chan] [arg logw] [arg logr]]

This command creates an observer transformation on top of the channel
[arg chan] and returns its handle. The channel handles [arg logr] and
[arg logw] are there the data is copied to.

[list_end]

[vset CATEGORY virtchannel]
[include ../common-text/feedback.inc]
[manpage_end]
